Coruscation

Calabria, like other southern Italian regions rich in agriculture, has long benefited from hefty European Union agricultural subsidies. To prevent fraud in which small acreage yielded puzzlingly large harvests, in 2007 the European Union changed its rules to base subsidies on the number of hectares planted rather than the tons produced.

The result, some authorities hypothesize, is that it may be more lucrative for some Calabrian landowners to let their harvests rot on the tree and collect the subsidies than to pay pickers. In theory, the migrants may have become less useful and, possibly, less tolerated.

Still, the violence was dramatic. After immigrants struck residents and shops with sticks and burned and smashed cars, residents began responding with violence. By late Saturday night, most immigrants feared for their safety and voluntarily boarded buses and trains that took them to immigrant detention centers elsewhere in southern Italy, Rosarno authorities said.